Elevator safety device



Dec 1,517,936.

R. C. BAKER ELEVATOR SAFETY DEVICE Filed Oct. 10, 1925 4 Sheets-Sheet l Reuben Baker IAVENTOR.

A ITORNEYJ.

R. C. BAKER ELEVATOR SAFETY DEVI CE Dec. 1924- 1,517,936

Filed 1923 4 Sheets-Sheet 2 in Q 1 ilk Ila E ia WEE

Reuben C. Baker I NVEN TOR.

. ATTORNEYJ:

Egg, 2, 1924-,

R. C. BAKER ELEVATOR SAFETY DEVICE Filed Oct. 10, 1923 4 Sheets-Sheet s i m if Feubefl C. Baker I INVENTOR.

Dec. 2, 1924- 1,5173% R.- C. BAKER ELEVATOR SAFETY DEVICE Filed Oct. 10, 1923 4 Sheets-Sheet 4 Feubew C. Baker I INVENTOR.

235%; n M Q M AITTORNEYJZ which further Patented Dec. 2, 1924. V

REUBEN C. BAKER, OF COALINGA, CALIF rennet tries.

ORNIA, ASSIGNOR T0 BAKER CASING SHOE COMPANY. OF COALINGA, CALIFORNIA, A CQRIE'OBATION OF CALIFORNIA.

ELEVATOR SAFETY DEVICE.

" Application filed. October 10, 1323. Serial No. 667,759.

To all whom it may concern.

Be it known that I, REUBEN C. BAKER. a citizen of the United States residing at Coalinga, in the county of Fresno and State of California. have invented certain new and useful Improvements in Elevator Safety Devices; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

he present invention relates to improvements in elevator safety devices in which provision is made for stopping the car or cage in the event of excessive speed or of the failure of the hoisting and lowering mechanism.

An object of the invention is to provide a device that is positive in its action of gripping the rails and one that requires very little power to actuate.

Another object of the invention is to pro vide a safety device in which the tension on the governor cable will be light due to the small amount of pull necessary to actuate the mechanism and furthermore in which the danger of over straining the governor cable to the breaking point is eliminated.

A further object of the invention is to produce a device of this character in which a positive and strong gripping action is secured through the use of wedges which tend to set themselves against the rails after being brought into contact therewith, but in positive actuating means is employed to secure the mechanical setting of these wedges.

And still further objects of the invention are to produce a safety device for elevators in which there is simplicity of construction with small liability of failure through defective parts; in which a minimum number of parts is used contributing to make an economical device and in which the device is compact in its general organization; ano to produce a device in which large bearing areas are afforded whereby to distribute the friction over large surfaces competent to take care of the work that must be done in the bringing of the car to a stop without exceeding the margin of safety.

With the foregoingand other objects in View, the invention will be more fully described hereinafter, and war he more partie ularly pointed out in the claims appended hereto.

In the drawings wherein like symbols refer to like or corresponding parts throughout the several views:

Figure 1 is a side view of an elevator showing the counter weight and control cable.

Figure 2 is an enlarged sectional view taken through the improved safety mechanisms and showing the parts in one position.

Figure 3 is a substantially right angles to Figure 2.

Figures 4 and 5 are details of the gearing.

Figure 6 is a fragmentary and sectioned perspective view showing the arrangement of the wedges and the driving mechanisms. Figure 7 is an elevation of a pair of the wedges, and igure 8 is a view similar to Figure 2 with parts in a subsequent position. eferring more particularly to the drawings l designates the cage or car, and 2 the rails upon which the car travels, these rails being of the cross section as indicated in Figure 3 and having central webs projecting therefrom.

At 3 is designated the cable running over the rollers as shown in Figure 1 and being connected with the counter weight 4. The safety device isvdesignated generally at 5 in Figure l and a cable 7 is shown as extending from the safety device, this being a branch cable coupled to the governor cable 6 mounted upon the rollers 8 at the side of the elevator shaft. The governor cable 6 is engaged by the pivoted gripping members 9. In accordance with a well known mechanism and operation the governor is so designed that vif it is driven faster than the tripping speed at which it may be set, the grips 9 are released and grip the cable 6 bringing it to a stop. Thereupon the branch cable 7 gets into play and operates the safety device.

Figures 2, 3 and 8 the branch cable 7 is shown as wound about a drum 10 having the internal threads to engage with the threads upon one end of the shaft 11. This shaft is journaled in bearings in the frame parts 12 and 22 and it is capable of rotation and also of a sliding movement (compare Figures 2 and 8). Theshaft 11 is providedwith a worm 30 interr'nediate thereof and disposed engagement with? aworm segment: 145 en the horizontal section taken at gaged loosely about the adjacent ends of the shaft sections 15 and 15 which are disposed substantially at right angles to the slidable shaft 11 and above the same. The worm segment is more nnrticularly shown in Figure 5 and carries a bevel pinion 31 adapted to mesh with the similarly toothed arms 23 carried by the collars 82 affixed to the shafts 15 and 15. This gearing an rangement provides a differential effect in order that uniform movement may be communicated to the shaft sections 15 and 15.

Each shaft section shown to best atvantage in lfigure (i provided upon its outer end with a pinion 16 disposed in mesh "with a rack 33 carried upon or formed with the adjacent of a pair of wedges 17 which are slidably mounted upon opposite sides of the web portions of the rails 2. The wedges are slidable in a channel guide 18 affixed to a suitable part of the car and the channel being of wedged shape in order to cause a clamping of the wedges 17 upon the web member when such wedges are elevated in the channel guide .18. The wedge blocks or members 17 are provided with dove-tail tongues 3 1 slidable in complementary grooves in the channel guide in order to properly center and guide the wedge blocks in their movement.

To one of the blocks 17, for instance that block which is equipped with the rack 33, are secured plates or strips 2 1- affixed as by the screws 36 or other fastening means, the plates being rigid with this block but having their opposite ends playing freely in transverse grooves made in the companion wedge block. The arrangement is such that the wedge block having the rack may raise the opposite wedge block through the plates 21- engaging the walls of the grooves 35 but the arrangement of the grooves permits of the second wedge block sliding upon the plates 2e toward and away from the first wedge block in accordance with the demand for this movement made upon the wedge blocks by the wedge shape of the channel guide 18. This arrangement of the two blocks is shown more particularly in Figure 7.

The shaft 11 projects beyond the bearing 12 as shown in Figures 2 and 8 and carries a dog 13 adapted to engage a part of the frame work for preventing the rotation of the shaft 11 until the dog reaches the position substantially as shown in Figure 8. In other words the shaft 11 is compelled initially to slide in an axial direction without rotary movement until the dog 13 escapes from the frame part and it is then free to rotate.

The action is as follows When the wedge blocks 9 stop the governor cable 6 as shown in Figure 1, the branch cable 7 is arrested in its movement and it promptly begins to unwind from the drum 10 causing a rotation of the drum which by reason of its abutment against the arm of the frame and further by reason of its threaded engagement with the shaft 11 causes such shaft to travel in an axial direction from the position shown in Figure 2 to substantially that shown in Figure 8. During this movement the worm 8O acts as a rack bar to the worm wheel or segment L1 through a. certain angular distance. This partial rotation of the worm wheel 1s is comnuniicated to the arms and thence to the shaft sections 15 and 15', the pressure being equalized through the differential arrangement.

Movement of the shaft sections 15 and 15 results inturning of the pinions 16 and causing ultimately raising of the wedge blocks 17. Due to the disposition of the contacting surfaces of the wedge blocks and the guide member 18, the wedge blocks are brought together upon the webs of the rails 2 when thus elevated and are in a position to receive the desired amount of pressure in stopping the car. This amount of pressure is then brought to bear by the rotation of the shaft 11., the dog 13 at this juncture being free of the frame member. The worm will then turn in the teeth of the worm segment 1 1 and exert a very powerful effect to turn the shaft sections 15 and 15 and to apply a high pressure to the wedge blocks such as will effectually stop the ear.

The thread in the drum 10 acts as a key to turn the shaft after the dog 13 no longer restrains its turning movement and the pitch of the thread being much greater than the pitch of the worm, the arrangement prevents the forcing backward of the shaft through the drum. If one guide rail 2 should be worn or there should be some defeet in the workmanship on the wedges and the same were made not of the same thickness the differential arrangement will compensate for this.

It will be appreciated from the foregoing that an extremely high pressure is applied to the wedge blocks through a very simple arrangement without causing undue strain on any of the cables; that the mechanism for accomplishing this result is compact, of few and simple parts and is of a nature susceptible of being readily installed upon existing constructions.

It is obvious that various changes and modifications may be made in the details of construction and design of the above specifically described embodiment of this invention without departing from the spirit thereof, such changes and modifications being restricted only by the scope of the following claims.

"What is claimed is 1. In an elevator, guide rails, a car, a

governor cable, a branch cable extending from the overnor cable, a drum receiving the branch cable and carried by the car, a shaft driven longitudinally and rotatable through the rotation of said drum, a worm carried by said shaft, a worm wheel meshing therewith, shaft sections, a differential for driving the shaft sections from said worm wheel, and pressure shoes bearing on the guide rails and operated on movement of the shaft sections.

2. The combination with elevator rails, a car movable thereon, and a governor cable, of a branch cable secured to the governor cable, a drum carried by the car and receiving said branch cable, a rotatable and slidable shaft having threaded engagement with the drum, means for initially permitting sliding movement of the shaft but subsequently allowing rotary movement thereof, a worm wheel, a worm carried by the shaft and meshing with the worm wheel, and shoes engaging the guide rails and movable thereagainst by action of said worm wheel.

3. In an elevator, the combination with guide rails, a car movable thereon, and a governor cable, of wedge shoes engaging at opposite sides of said guide rails, guides for the shoes adapted to direct same against the rails, means for moving said shoes in the guides, said means comprising a worm and a worm wheel having connections to the shoes, and means associated with the governor cable for initially moving the worm longitudinally in contact with the worm wheel and for subsequently rotating said worm in mesh with the worm Wheel.

4. A safety device for elevators comprising a normally stationary drum held against movement in one direction, a shaft having threaded engagement with the drum, means for preventing the shafts rotation through an initial period of the drums rotation whereby to shift the shaft longitudinally only for this period, said drum. adapted to rotate the shaft during the remainder of its movement, brake shoes for stopping the elevator, means driven by said shaft during its axial initial movement for moving the shoes into operative position and for finally compressing the shoes with great pressure on the rotary movement of said shaft.

guide 5. A safety device for elevators comprising a longitudinally movable and rotary shaft having a thread cut in one end, a drum engaging the thread, a cable wound on the drum for rotating the same, means for holding the drum against sliding movement in one direction, means associated with the shaft for preventing the rotation of the shaft during the initial rotation of the drum but for subsequently allowing rotation of said shaft, a worm upon the shaft, a worm wheel segment meshing therewith, a pair of shaft sections, a differential disposed between the worm segment and the shaft sections, pairs of brake shoes mounted at op posite ends of said shaft sections, one of each pair of shoes being directly driven by said shaft sections, and a connection between the pairs of shoes for causing the simultaneously movement thereof.

6. A safety device for elevators comprising pairs of brake shoes adapted to come together upon opposite sides of the guide rails, one of said shoes having transverse grooves, plates carried by the other of the shoes for engaging slidably in said trans verse grooves and for coupling the shoes together for longitudinal movement, wedge shaped guides for directing the movement of said shoes, and means for moving the shoes in said guides.

7. A safety device for elevators comprising pairs of wedge shoes adapted to come together upon the guide rails of the elevator, means for moving one of the shoes longitudinally, coupling means between the shoes adapted to move the second shoe with the driven shoe but to allow the shoes to expand and contract laterally without interference, and a channel guide of wedge shape for directing the shoes against the rail.

8. In an elevator safety device, a pair of wedge shoes adapted to come together upon opposite sides of the guide rails, one of the shoes having a rack thereon, a pinion engaging the rack, a shaft for driving the pinion, means whereby said shaft may be put in motion, means for guiding the shoes when shifted, and means for coupling the shoes for simultaneous movement but allowing free lateral expansion and contraction.

REUBEN C. BAKER. 

